Australia’s mean temperature last year was 0.56C warmer than the long-term average despite 2021 being the country’s coolest year in a decade.
It was a year of contrasting weather and climate conditions, the Bureau of Meteorology said in its annual climate statement, with long-running heatwaves in northern Australia and widespread flooding in eastern states, in part due to a La Niña event.
In the west, severe tropical cyclone Seroja was the southernmost tropical cyclone to make landfall since the 1950s.
Averaged across the continent, last year was Australia’s 19th warmest year on record.
Mean annual maximum and minimum temperatures were above average for most of northern Australia, Tasmania, and parts of the west coast, but temperatures were cooler than average for parts of inland New South Wales and central Australia.
“Although 2021 was Australia’s coolest year since 2012, temperatures were still much warmer than the historical average,” said climatologist Jonathon Pollock. “In fact, of all the years on record prior to the year 2000, only five were warmer than 2021.”
The Intergovernmental Panel on Climate Change last year reported that Australian land areas were on average 1.4C hotter than early last century, and warming was unequivocally due to human influence.
The country had its wettest November on record in 2021 and across the year experienced its highest rainfall levels since 2016. Nationally averaged rainfall was 9% above the 1961–1990 average, with 509.7mm. For much of Australia the amount of rainfall was above average compared to all years since 1900.
The wetter weather was influenced by several climate drivers, including La Niña, which persisted through the 2020-21 summer and emerged again in November.
A negative Indian Ocean dipole in winter and spring fuelled above-average winter–spring rainfall over parts of southern Australia, compared to the distribution of rainfall across all years since 1900.
“Two years in a row of above average rainfall meant by the end of 2021, and for the first time in five years, no large parts of the country were in meteorological drought,” said Pollock.
He said major water storages across eastern Australia had recorded significant increases. In western NSW, the Menindee Lakes filled for the first time since 2012.
There were some exceptions, however. The most significant was in south-east Queensland, where water storages have remained low.
